As Bigdave says I am currently building the Lafayette kit, and am very impressed with it so far. I can't speak on how well the bayonet seal works, because I haven't gotten that far yet.
I also have the Patrick Henry kit, which I named the Abraham Lincoln. This kit I bought probably 10 years ago and have run it at several of the Sub Regattas. It runs great and the quality of the fiberglass work is very good. A couple of things to consider is that it is NOT a scale kit by any means, and it probably weighs about 50 lbs when it is ready for the water. This is because the inside of the hull has to be sealed and waterproof, it's a "dry hull" design. This means you can't pick up additional water weight like the wet hull designs; so all your weight has to be inside the hull all the time. Even though it is pretty big inside the hull, it is still difficult to work on when everything is mounted in the hull. You can remove the Engel tanks and your radio equipment, but I found that this took alot of manuevering to get them out the hatch. Luckily I don't have to remove them very often. I also didn't like the hatch sealing method they used, so I made my own seal out of RTV, and my own hatch cover out of lexan. I am now on my second RTV seal because I was worried about its age, and it was getting thinner every year. The first seal lasted about 8 years with no leaks. Hope this helps.